/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
 * All rights reserved.                                                *
 *                                                                     *
 * Redistribution and use in source and binary forms, with             *
 * or without modification, are permitted provided that the            *
 * following conditions are met:                                       *
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 *     * Redistributions of source code must retain the                *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer.                                       *
 *                                                                     *
 *     * Redistributions in binary form must reproduce the             *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer in the documentation and/or            *
 *     other materials provided with the distribution.                 *
 *                                                                     *
 *     * Neither the name of Paul Mineiro nor the names                *
 *     of other contributors may be used to endorse or promote         *
 *     products derived from this software without specific            *
 *     prior written permission.                                       *
 *                                                                     *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND              *
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,         *
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES               *
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE             *
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER               *
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,                 *
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES            *
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE           *
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 * Contact: Paul Mineiro <paul@mineiro.com>                            *
 *=====================================================================*/

#include "squaredloss.hh"

#include <cstring>
#include <stdexcept>

namespace
{
  using namespace flassol;

  Loss*
  make_squared_loss (const std::string& s)
    {
      if (s != "squared")
        {
          throw std::invalid_argument ("squared loss does not take arguments");
        }

      return new SquaredLoss;
    }

  void
  eat_white (char*& p)
    {
      while (isspace (*p))
        {
          ++p;
        }
    }

  Loss*
  make_squaredclipped_loss (const std::string& s)
    {
      std::string::size_type openparen = s.find_first_of ("(", 0);

      if (openparen == std::string::npos)
        {
          return new SquaredClippedLoss;
        }
      else
        {
          const char* c = s.c_str () + openparen + 1;
          char* endptr;
          boost::optional<float> min;
          boost::optional<float> max;
          Loss* rv = 0;

          if (strncmp (c, "undef", 5) == 0)
            {
              endptr = const_cast<char*> (c) + 5;
            }
          else
            {
              min = strtof (c, &endptr);
            }

          if (*endptr == ',')
            {
              ++endptr;
              eat_white (endptr);

              if (strncmp (endptr, "undef", 5) == 0)
                {
                  endptr = endptr + 5;
                }
              else
                {
                  max = strtof (endptr, &endptr);
                }
            }

          if (*endptr == ')' && (! max || ! min || *max >= *min))
            {
              rv = new SquaredClippedLoss (min, max);
            }
          else
            {
              throw std::invalid_argument ("specify as 'squaredclipped (min, max)' ; where max >= min || max = 'undef' or min = 'undef'; initial limits will automatically expand as wider labels are encountered ; 'squaredclipped' is equivalent to 'squaredclipped (undef, undef)'");
            }

          return rv;
        }
    }
}

namespace flassol
{
  LossFactory SquaredLoss::factory = register_loss_factory ("squared",
                                                            make_squared_loss);

  LossFactory SquaredClippedLoss::factory = 
    register_loss_factory ("squaredclipped",
                           make_squaredclipped_loss);
}
